1. Field of the Invention
The present invention relates to a break-in detection system for detecting intrusion into a building or premises by means of sensors so as to operate in coordination with a monitoring system using with ITV cameras provided for the detection purpose.
2. Description of the Related Art
Recently, conventional and new systems are drawing a wide attention for prevention or surveillance of intrusion into buildings or premises. There are many systems in which detection sensors are installed in coordination with a monitoring system for alarm/confirmation purposes.
The detection sensors include a vibration sensor, an infra-red ray interception sensor, an electric field interception sensor, a mechanical tension sensor, surveillance monitor sensor for detecting occurrences of abnormal state of affairs, or the like. Further, there is proposed an optical fiber sensor using optical fibers (as disclosed in Japanese Patent Appln. Laid Open to Public No. 2001-296111), in which whether or not optical signals issued from the optical fibers are being reflected by an article subject to detection (or whether or not the article subject to detection is present at a predetermined position) is determined by the presence/absence of reflection.
The surveillance system operated in coordination with the detection sensors includes a recording method of ITV (Industrial Television) camera images and remote monitoring, an image analysis method, an alarm signal type method by use of an alarm unit and a wireless warning method.
The reliability of such break-in detection system is influenced by the sensitivity of detection sensors, the installation locations thereof and the resultant frequency of false alarms. If the system issues too many false alarms, the purposes of the use thereof will not be accomplished.
Further, there is a need for administering the break-in detection system to maintain the functions thereof in a predetermined state. If such maintenance is required in too many locations, the running cost thereof will increase.
For the above reasons, maintenance free break-in detection systems having superb reliability are much in demand.
As for reliability, tension sensor types may be recommended in the light of the most abundant track records though the conventional tension wire type has the problem of electromagnetic interference caused by its components and requires replacement of parts due to exposure to the external environment as well as aging with the result that there is the need for curtailment of the running cost and improvement in maintenance efficiency is reported to arise.
In terms of maintenance-free requirement, the surveillance system incorporating ITV cameras less susceptible to the external environmental factors (such as winds, snowfalls, temperatures, humidity, electromagnetisms or the like) may be recommended but calls for a large number of ITV cameras to be installed and long signal cables to be laid down in a long distance as far as the central monitor room if the surveillance area is extensive, thus requiring a large scale system.
The object of the present invention is to provide a break-in detection system excellent in reliability and meeting the maintenance free requirement.